Chemistry - Atomic Structure and Periodic Properties of Elements
Exam Duration: 45 Mins Total Questions : 30
Bohr radius of nth orbit of an atom is given by the expression
- (a)
\(\quad r=\frac { { n }^{ 2 }{ h }^{ 2 } }{ 4{ \pi }^{ 2 }mZ{ e }^{ 2 } } \)
- (b)
\(\quad r=\frac { { n }^{ 2 }{ h }^{ 2 } }{ 4{ \pi }^{ 2 }mZ{ } } \)
- (c)
\(\quad r=\frac { { n }^{ 2 }{ h }^{ 2 } }{ 4{ \pi }^{ 2 }m{ e }^{ 2 } } \)
- (d)
\(\quad r=\frac { { n }^{ }{ h }^{ } }{ 4{ \pi }^{ 2 }m{ e }^{ 2 } } \)
The velocity of electron in the first Bohr orbit of hydrogen atom would be (radius of the first orbit given as 0.53X10-10m)
- (a)
4.4 X 106m s-1
- (b)
3.3 X 106m s-1
- (c)
2.2 X 106m s-1
- (d)
1.1 X 106m s-1
The wavenumber of different lines in hydrogen spectrum is given by \(\overline { V } ={ R }_{ H }\left( \frac { 1 }{ { { n }_{ 1 } }^{ 2 } } -\frac { 1 }{ { { n }_{ 2 } }^{ 2 } } \right) \) where R= 1.0967800 X 107 m-1. The wavelength of the first line of lyman series would be
- (a)
1.22X10-7m
- (b)
9.1176X10-8m
- (c)
12.2X10-7m
- (d)
122X10-7m
One atom of an element X weighs 6.644X10-23 g. The number of gram atoms in 40 kg of it would be
- (a)
10 g-atom
- (b)
100 g-atom
- (c)
1000 g-atom
- (d)
1 g-atom
The volume of a gas in an electronic tube is 1.12X10-7 ml at STP. The number of molecules of the gas in the tube would be
- (a)
3.01X108 molecules
- (b)
3.01X1010??????? molecules
- (c)
3.01X1012????? molecules
- (d)
3.01X1014??????? molecules
The orbital is a space where the probability of finding an electron is
- (a)
95-98%
- (b)
50%
- (c)
0%
- (d)
100%
The element with highest electronegativity is
- (a)
chlorine
- (b)
fluorine
- (c)
nitrogen
- (d)
oxygen
The quantum number +1/2 and -1/2 for the electron spin represent
- (a)
rotation of electron in clockwise and anticlockwise direction respectively
- (b)
rotation of the electron in anticlockwise and clockwise directions respectively
- (c)
magnetic moment of the electron pointing up and down respectively
- (d)
two quantum mechanical spin states which have no classical analogue.
Which one -of the following is correct order of the size of iodine species?
- (a)
\(I>\overset { - }{ I } >\overset { + }{ I } \)
- (b)
\(I>\overset { + }{ I } >\overset { - }{ I } \)
- (c)
\(\overset { + }{ I } >\overset { - }{ I } >I\)
- (d)
\(\overset { - }{ I } >{I}>\overset { + }{ I } \)
For azimuthal quantum number l=3, the maximum number of electrons will be
- (a)
2
- (b)
6
- (c)
0
- (d)
14
Krypton (36Kr) has the electronic configuration(18Ar)4s2,3d10,4p6; the 37 th electron will go into which of the following subshells?
- (a)
4f
- (b)
4d
- (c)
3p
- (d)
15s
the common set of quantum numbers for unpaired electron of chlorin atom is
- (a)
3,0,1
- (b)
3,1,2
- (c)
3,1,1
- (d)
3,0,0
If the radius of first bohr orbit be a0,then the radius of third Bohr orbit would be
- (a)
3 X a0
- (b)
6 X a0
- (c)
9 X a0
- (d)
1/9 X a0
Splitting of spectral lines under the influence of magnetic field is called
- (a)
Stark effect
- (b)
Zeeman effect
- (c)
Photoelectric effect
- (d)
none of these
The radius of an atom is of the order of
- (a)
10-10 cm
- (b)
10-13 cm
- (c)
10-15 cm
- (d)
10-8 cm
Atomic number is equal to the
- (a)
number of neutrons in the nucleus
- (b)
number of protons in the nucleus
- (c)
sum of protons and neutrons
- (d)
atomic mass of the element
It atomic numbers of nickel and copper are 28 and 29 respectively, which of the following does the electronic configuration 1s2 2s2 2p6 3s2 3p6 3d10 represent?
- (a)
Cu+
- (b)
Cu2+
- (c)
Ni2+
- (d)
Ni
The valence orbital configuration of an element with atomic number 23 is?
- (a)
3d5
- (b)
3d3, 4s2
- (c)
3d3 ,4s1,4p1
- (d)
3d2,4s2,4p1
22Na contains
- (a)
22 protons
- (b)
11 neutrons
- (c)
22 neutrons
- (d)
none of these
Which of the following has the largest size?
- (a)
Br-
- (b)
I
- (c)
I-
- (d)
I+
The meting point is lowest for
- (a)
Be
- (b)
Mg
- (c)
Ca
- (d)
Sr
The element with atomic number 55 belongs to which block of the periodic table?
- (a)
s-block
- (b)
p-block
- (c)
d-block
- (d)
f-block
Among the elements given below, the one with highest electropositivity is
- (a)
Cu
- (b)
Cs
- (c)
Cr
- (d)
Ba
Which o fthe following elements is/are not liquid at \({ 30 }^{ \circ }\)C?
- (a)
Ga
- (b)
Hg
- (c)
Ge
- (d)
Cs
Which of the following has greatest tendency to lose electron
- (a)
F
- (b)
Fr
- (c)
S
- (d)
Be
Which of the following is the smallest in size?
- (a)
N-3
- (b)
O2-
- (c)
F-
- (d)
Na+
Which of the following represents element in order of increasing atomic size
- (a)
I, Br, CI
- (b)
Na, Mg, C
- (c)
C< N< O
- (d)
Li,Na,K
The pair of ions having same electronic configurations is
- (a)
Cr3+, Fe3+
- (b)
Fe3+, Mn2+
- (c)
Fe3+, Co3+
- (d)
Sc3+, Cr3+
Which of the following nuclear reactions will generate an isotope?
- (a)
Neutron particle emission
- (b)
Positron emission
- (c)
\(\alpha\) - particle emission
- (d)
\(\beta\) - particle emission